426 THE EVOLUTION OF THE METAZOA 



of the Sipunculoidea— under the name Derosomes, yet he 

 placed them within the framework of "Les Vers." Ulrich 

 (1950) has also united, as we have done, all these groups (with 

 the exception of the Sipunculoidea) but he used here different 

 names (Tentaculata for three of our classes, and Entcropneusta 

 for two of our classes); at the same time we find in his work 

 the Chaetognatha accompanied by a question mark as a sign 

 that Ulrich could not come to any decision regarding the 

 classification of this truly aberrant group. The Sipunculoidea 

 are also equipped by Ulrich with a question mark. The frame 

 work, however, of this group is in Ulrich entirely different 

 from the sphere of our Oligomeria. All these groups are placed 

 under the name Archicoelomata (as a counterpart to the Neo- 

 coelomata which again are equipped with a question mark) at 

 the beginning of the Bilateria (Coelomata). This must be inter- 

 preted in such a way that Ulrich believes that all these animal 

 groups have primarily few or no segments; correspondingly 

 we find the Platyhelminthes with the Nemertini, Endoprocta, 

 and the Priapulida placed at the end of the system, together 

 with the Protostomia which are preceded by the Deuterostomia. 

 It is noteworthy to see that Ulrich inclines to judge "die 

 Evolution des heutigen Cnidarenmaterials nicht als progressiv, 

 sondern als regressiv." In his text Ulrich makes a good ob- 

 servation regarding the widely accepted division of the Coe- 

 lomata into the Protostomia and the Deuterostomia. He states, 

 "sie (sc. this division) wird jedoch der tatsachlichen Mannig- 

 faltigkeiten nicht gerecht, tut den Dingen mancherlei Zwang 

 an und gedenkt die im einzelnen ungeheuer heterogenen, 

 bruchstiickartigen Producte einer unermasslichen Evolution 

 bereits mit einem intimen Einzelmerkmal regieren zu konnen." 

 Ulrich stands clearly too much under the influence of the 

 ideas that had been proposed by Remane. 



We have not accepted the division of the Eumetazoa into 

 the Protostomia and the Deuterostomia as such a division 

 could not represent an actual phyletic development. We are 

 therefore not hindered in uniting all the groups of the Eumeta- 



